Early diagnosis and treatment of Lyme disease is associated with an improved clinical outcome, and is recommended to prevent subsequent manifestations such as arthritis and cranial paralysis. Unfortunately, early diagnosis of Lyme disease has been hampered because B.burgdorferi antigens and the human humoral response to them have been only partially characterized, and because there are no reliable serological assays for diagnosis of the disease. We propose to develop immunodots and ELISA assays for diagnosis of Lyme disease based on cloned B. burgdorferi gene products that are human immunogens. We shall investigate sensitivity and specificity of these diagnostic assays. The B. burgdorferi gene-products to be used are distinct from all characterized antigens as OspA/OspB, OspC, flagellin and heat-shock proteins. In preliminary studies, we have identified a single clone from a lambdagt11 B.burgdorferi library expressed in E. coli that reacted only with sera from patients with Lyme disease and failed to react with anti-OspA/OspB, anti-OspC or anti-flagellin antibodies or with sera from normal controls. We will finish sequencing the DNA from this clone, characterize its gene-products biochemically, and partially purify them. Recombinant B. burgdorferi antigens will be analyzed in ELISA and immunodot binding assays for their ability to discriminate between sera from patients with Lyme disease, sera from patients with other infectious diseases, and sera from normal individuals.